Work It: 6 High-Tech Workout Gadgets

You don't have to guess or crunch numbers to know if you are giving it all you've got or going slow and steady--the latest high-tech gadgets gauge how hard (or easy) you're working. It's that simple. But if you prefer the old-school way...

Follow your heart. Love your heart-rate monitor? Take note of the target zones you want to reach. Start by calculating your maximum heart rate (MHR): 206 – (0.88 x age). For a 30-year-old, that would be 180 beats per minute (BPM). Then multiply that number by the percentages below to calculate your training zones.

Pear Square One
This smart training system connects you to one of 500 unique, customizable plans that give you a real-time coach, biofeedback and more for up-to-the second training and data. $249.99; PearSports.com